Whey, which is a residual product in cheese and caseine production, is one of the largest protein reserves which until only recently has begun to be employed as a raw material in food production. Whey constitutes 80-90% of the milk which is employed in cheesemaking and it contains approximately 50% of all of the nutrient substances which are originally to be found in the milk.
Whey is concentrated to WPC (Whey Protein Concentrate) by micro- or ultra filtration. WPC constitutes the retentate from this process and WPC also constitutes substantially that raw material for which the method according to the present invention is intended.
In order to expand the practical fields of application of whey proteins, it is most general practice today to cause the whey concentrate to undergo a microparticulation. Microparticulation implies that the whey proteins, by heat treatment, are denaturated and aggregated, i.e. are lumped together, whereafter the aggregations, as a result of mechanical processing, are divided into smaller particles. As a result of microparticulation, a product will be obtained which can be employed in many different food products. The denaturated whey protein will have another flavour and a different appearance from the original whey protein, which also contributes to increasing the use of whey protein in the food industry.
International Patent Application WO 2006/024395 A1 describes a microparticulation process where whey concentrate is heat treated and thereafter subjected to a mechanical processing. The heat treatment takes place in a scrape heat exchanger and the mechanical processing in a homogeniser.